The long term goal of this research is to develop a new approach to the evaluation of microregional circulation. This research is based on the working hypothesis that fluorescent microspheres can be spatially located by fluorescence imaging of organ serial sections. During Phase I a computer-controlled imaging system was assembled and methods successfully developed to obtain and analyze regional flow from images of fluorescent microspheres embedded in perfused rat hearts. Phase I studies demonstrated the feasibility of the working hypothesis in a small organ. Phase II will work on the development of an instrument to examine larger tissue blocks and demonstrate the application of this technology to physiological studies in the grantee's laboratory and through subcontracts with researchers in bioengineering and pulmonary medicine. This project will provide researchers with the a rapid and automatic instrument for evaluating microregional flow in tissue using at the resolution limits of microsphere technology. This technology reduces the time of currently employed microsphere procedures while markedly increasing spatial resolution. Radiation exposure of workers and radioactive carcass disposal are eliminated. New capabilities will allow researchers to compare microsphere density with anatomical features. PROPOSED COMMERCIAL APPLICATION: Instrumentation and methods to rapidly and automatically map microspheres in animal tissue by video imaging will have application to a wide variety of tissue circulation studies that currently employ radioactive or fluorescent microspheres with labor intensive, costly or hazardous counting and analysis procedures.